Naypyitaw (Myanmar): UN Secretary-General Ban Ki-moon met Myanmar President Thein Sein on Monday to offer international help for reform in the long-isolated state and will later become the first foreign dignitary to address its fledgling parliament.

On his first visit to Myanmar since its year-old, quasi-civilian government embarked on a wave of political and economic liberalisation, Ban described Thein Sein, a former top general, as a "key driver" of the reforms and said he would urge Western powers to ease sanctions further.

The new government, comprising mostly former generals in the military junta that ruled for half a century, has stunned the world with the pace of its reforms in a way that Ban said was impressive but still a work in progress.

"We need to support Myanmar so it doesn't slide back down the scale," Ban told reporters in the capital, Naypyitaw, on Sunday, the first day of a three-day visit.

Missing from parliament on Monday will be Nobel Peace Prize laureate Aung San Suu Kyi and members of her opposition National League for Democracy party, which won April 1 by-elections by a landslide.

Her party has refused to take their seats in protest at a swearing-in oath that requires new parliamentarians to pledge to protect the constitution.

Suu Kyi has vowed to revise the 2008 army-drafted constitution that gives the military wide-ranging powers, including the ability to appoint key cabinet members, take control of the country in a state of emergency and occupy a quarter of the seats in parliament.

"I'm sure they'll find a solution using their wisdom," Ban said.

Technical assistance

Ban's visit is his first since July 2009, when Senior General Than Shwe ruled Myanmar in a regime that brutally suppressed dissent.

But with former fourth-in-command Thein Sein now in charge, the government has eased media censorship, legalised trade unions, freed more than 600 political prisoners and begun an economic overhaul. It has also struck ceasefire deals with a dozen ethnic rebel armies.

Those and other reforms have convinced the European Union, United States, Australia and Canada to ease some sanctions in recent weeks, a move Ban said would allow the United Nations to increase its role in Myanmar's development.

He signed an agreement on Monday offering U.N. technical support for the country's first census since 1983 and will travel to Shan state, one of the world's biggest opium-growing regions, to assess moves to eradicate poppy cultivation.

He also plans to meet lower house speaker Thura Shwe Mann, a former general who once outranked the president, and government negotiators leading peace talks with ethnic rebels. A U.N. programme to connect local businessmen with Western counterparts will also be launched.